Polyamide fibers containing antistatic polyether and fatty acyl derivatives of amino acids

ABSTRACT

AN IMPROVED ANTISTIC POLYAMIDE FIBER IS PREPARED BY INCORPORATING IN THE FIBER ABOUT 1 TO 12 PERCENT BY WEIGHT OF A HIGH MOLECULAR WEIGHT PROPYLENE OXIDE-ETHYLENE OXIDE COPOLYMER BASED ON ETHYLENE DIAMINE AND ABOUT 0.5 TO 8 PERCENT BY WEIGHT OF AN AMINO ACID SALT HAVING THE FORMULA:   (R-CO-N(-R&#39;&#39;)-CH2-COO-)N-M   WHERE R IS AN ALKYL RADICAL CONTAINING AT LEAST 6 CARBON ATOMS R&#39;&#39; IS AN ALKYL RADICAL CONTAINING AT LEAST 1 CARBON ATOM, AND M IS AN ALKALI METAL OR ALKALINE EARTH METAL, AND N IS A WHOLE NUMBER CORRESPONDING TO THE VALENCE OF THE METAL.

United States Patent ABSTRACT OF THE DISCLOSURE An improved antistaticpolyamide fiber is prepared by incorporating in the fiber about 1 to 12percent by weight of a high molecular weight propylene oxide-ethyleneoxide copolymer based on ethylene diamine and about 0.5 to 8 percent byweight of an amino acid salt having the formula:

where R is an alkyl radical containing at least 6 carbon atoms, R is analkyl radical containing at least 1 carbon atom, and M is an alkalimetal or alkaline earth metal, and n is a whole number corresponding tothe valence of the metal.

BACKGROUND OF THE INVENTION This invention relates to a process for themelt-spinning of a filamentary structure from a synthetic polyamidepolymer. More particularly, it is concerned with a process for theformation of an improved antistatic filament, yarn or the like bymelt-spinning a synthetic linear fiberforming polyamide.

It has been suggested that the utility of synthetic fibers could beincreased and their properties, in particular'their antistaticproperties, could be improved if a polyalkylene ether of high molecularweight is included in the polymer. For example, it is disclosed in US.Pat. 3,475,898 to Magat and Sharkey to use poly(ethyleue-propylene)etherglycols for this purpose. More recently, US. Pat. 3,657,- 386 disclosesthat certain propylene oxide ethylene oxide copolymers based onetheylene diamine are especially useful in preparation of an antistaticfiber of polyamide. Although these patents represent importantimprovements in this art, research Work has continued in an elfort tofind still more efiective antistatic additives. Much of this researcheffort has been expended to develop an improved antistatic polyamidefiber which will retain its antistatic I properties after many washings.

SUMMARY OF THE INVENTION It is an object of this invention to provide aprocess for formation of an antistatic polyamide fiber from a fiber-.

forming polyamide polymer containing 1 percent to 12 percent by weightbased on the weight of the polyamide polymer of an antistatic tetrolcompound represented by the formula:

I CH: CH3 H(OCH:CH2): O HCH: CH2 K JHO (CI-T201110) H t t NCHQCHQN CH:CH: H(OCHzCH7)h 0 JIHCH: d CH2 (SE0 1, (CHzCHz O H where a, b, c, a, e,f, g, and h are each a whole number and the total of a, b, c and d isbetween 8 and 850 and the total of e f, g, and h is between 8 and 1,000;by extruding the molten polymer through an orifice into a quenchingmedium and thereafter stretching the resulting filaments, theimprovement comprising dispersing in the extrudate prior to extrusion atleast 0.1 percent by weight, preferably 0.5 to 8 percent, based on theweight of said polyamide polymer, of an amino acid salt having theformula:

where R is an alkyl radical containing at least 6, preferably 8 to 16carbon atoms, R is an alkyl radical containing at least 1, preferably 1to 4 carbon atoms, M is selected from the group consisting of alkalimetals and alkaline earth metals, and n is a whole number correspondingto, the valence of the metal.

The aminoacid-saltsuseful in the present invention are knowncompoundsand someare commercially available. They may be prepared inaccordance with the procedure of U.S. Pat. 2,729,657 or US. Pat.3,074,980.

The antistatic fiber of this invention may also contain conventionalfiber additives such as antioxidants, stabi-- lizers, delusterants,dyeing assists, and colorants.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now befurther described in the following specific examples which are to beregarded solely as illustrative and not as restricting the scope of theinvention.

The primary antistatic additives used in the example are tetrolcompounds having the general formula:

omono omcrnmm Ncnior'rm where a, b, c, d, e, f, g, and h are each awhole number and the total of a, b, c, and d is between 8 and 850 andthe total of e, f, g, and h is between 8 and 1,000. Suitable tetrolcompounds are commercially available (BASF- Wyandotte) under thetrademark Tetronic as a series of poly(oxyethylene)-poly(oxypropylene)block copolymers having molecular weights from 1,650 to over 26,000.This series varies in length of poly(oxyethylene) chain andpoly(oxypropylene) chain. A 3 and 4 digit code number A glass reactorequipped with a heater and stirrer was charged with a mixture of 1,520grams of e-caprolactam and 80 grams of aminocaproic acid. The mixturewas then flushed with nitrogen and was stirred and heated to 255 C. overa one-hour period at atmospheric pressure to produce a polymerizationreaction. The heating and stirring was continued at atmospheric pressureunder a nitrogen sweep for an additional 4 hours in order to completethe polymerization. During the last 30 minutes of the polymerization,2.8 grams of sodium lauroyl sarcosinate and 60 grams of the antistatictetrol compound Tetronic 1508 (molecular weight 27,000, with ethyleneoxide moiety making up 80% of the molecular weight) were added to thepolycaproamide and stirring was continued to thoroughly mix theadditives throughout the polymer. Nitrogen was then admitted to theglass reactor and a small pressure was maintained while the polymer wasextruded from the glass reactor in the form of a polymer ribbon. Thepolymer ribbon was subsequently cooled, pelletized, Washed and thendried. The polymer was a white solid having a relative viscosity ofabout 55 to 60 as determined by a concentration of 11 grams of polymerto 100 milliliters of 90 percent formic acid at 25 C. (ASTMD-789- 62T).

The polycaproamide pellets containing the Tetronic 1508 and the sodiumlauroyl sarcosinate were melted at about 285 C. and then melt-extrudedunder a pressure of about 1,500 p.s.i.g. through a 16-orificespinnerette, each of the orifices having a diameter of 0.014 inch, toproduce a 250-denier fiber. The fiber was then collected at about 1,000feet per minute and was drawn about 3.5 times its extruded length toproduce a 70-denier yarn. For convenience, this yarn hereinafter will becalled Yarn A. A control yarn containing the Tetronic 1508 but noadditional additives was produced in the same manner as described above.For convenience, this yarn hereinafter will be called Yarn B.

Yarn A and Yarn B were woven into conventional plain weave fabrics. Thefabrics were cut into fabric test samples having a width of 3 inches anda length of 9 inches. The fabric samples were tested for theirantistatic property in accordance with the general procedure describedin the Technical Manual of the American Association of Textile Chemistsand Colorists, 1969 edition, volume 45, at pages 206-207. This testprocedure is entitled Electrostatic Clinging of Fabrics: Fabric to MetalTest and is numbered AATOC 115-1969. In accordance with this test, YarnA and Yarn B both showed excellent antistatic properties; however, YarnA was significantly improved over Yarn B. That is, the average time forYarn A fabric samples to decling from metal completely on their own wasabout 70 seconds after 25 washes, whereas the average time for Yarn Bfabric samples was about 130 seconds after 25 washes.

Example 2 The procedure of Example 1 was followed except that noantistatic additive was added to the polycaproamide.

The average time for the yarn fabric samples to decling from metalcompletely was about 390 seconds after 25 washes. The textile industryaccepts 300 seconds or less as passing.

4 Example 3 The procedure of Example 1 was followed except that 2.8grams of sodium lauroyl sarcosinate (but no Tetronic 1508) was added tothe polycaproamide. The average time for the yarn fabric samples todecling from metal completely was about 250 seconds after washes.

Example 4 Example 5 The procedure of Example 1, Yarn A, was followedexcept that the antistatic additives were charged with the caprolactam.The average time for the yarn fabric samples to decling from metalcompletely was 75 seconds.

Example 6 The procedure and additives utilized in this example M weresimilar to Example 1, Yarn A, except that the polyamide was polymerizedfrom poly(hexamethylene ammonium) adipate salt. The average time for theyarn fabric samples to decling from metal completely Was 72 seconds.

Example 7 The procedure of Example 1 (Yarn A) was followed except that30 grams of the antistatic additive of Example 1 was used together with0.9 gram of tetraEmethylene 3 (3,5'di-tertiary-butyl-4'-hydroxyphenyl)propionate] methane. The fiberproduced was pale yellow and had a nub count of 0.8x 10 nubs per poundof yarn.

Example 9 Polycaproamide pellets containing the antistatic agents ofExample 1, i.e., sodium lauroyl sarcosinate and Tetronie 1508, wereprepared in accordance with the procedure of Example 1. Thepolycaproamide pellets were melted at about 285 C. and then meltextruded under pressure of 15 p.s.i.g. to a 70-orifice spinnerette, eachof the orifices having a diameter of 0.018 inch to produce a 4,500denier fiber. The fiber was collected at 1,000 feet per minute and wasdrawn about 4 times the extruded length to produce 1,125 denier yarn.

The yarn was textured using a steam jet and two-plied. Then, the yarnwas tufted into a level loop carpet at 6.5 stitch rate, 9- inch pileheight, mock dyed and latexed. Static buildup of the carpet was testedby a shufile test measuring the electrostatic voltage build-up on aperson walking with a series of short shuffiing steps on a piece ofcarpet conditioned at 70 F. at 20% relative humidity. The voltagegenerated was 3.6 kv. A control carpet prepared with no antistaticadditive generated 10 kv.

Discussion: In additional tests, it was determined that the molecularweight of the antistatic tetrol compound is preferably between about4,000 and about 50,000, the ethylene oxide moieties making up about 20%to about of the molecular weight of said compound. Preferably, theantistatic fiber contains from about 2 percent to about 8 percent of thetetrol compound plus 0.5 to 8 percent of the instant amino acid salthaving the formula:

R 0 R-(J-iI-CHz-h-OM where R is an alkyl radical containing 8 to 16carbon atoms, R is an alkyl radical containing 1 to 4 carbon atoms, andM is an alkali metal. The weight ratio of the amino acid salt to thetetrol compound is preferably between 0.02 and 0.2.

By antistatic fiber is meant fibers that will pass the cling test andthe shufile test as described in US. Pat. 3,657,386. By fiber is meantmultifilament yarn, monofilament, and all the known physical forms ofsynthetic fibers. By polyamide is meant the polymers made bycondensation of diamines with dibasic acids or by polymerization oflactams or amino acids, resulting in a synthetc resin characterized bythe recurring group -CONH-. By ethylene oxide moiety is meant theportion of the chemical molecule (CH CH O)-. The term nubs isconventionally applied and is used herein to mean enlarged sections offilament no more than several filaments in length.

Desirably, the antistatic additives are substantially uni formlydispersed in the polyamide.

We claim:

1. In a process for the formation of an antistatic polyamide fiber froma fiber-forming polyamide polymer containing 1 percent to 12 percent byweight of an antistatic tetrol compound represented by the formula:

where a, b, c, d, e, f, g, and h are each a whole number and the totalof a, b, c, and d is between 8 and 850 and the total of e, f, g, and his between 8 and 1,000, said antistatic tetrol compound having amolecular weight between about 4,000 and about 50,000, and said ethyleneoxide moieties making up about 20 percent to about 80 percent of saidantistatic tetrol compound, by extruding the molten polymer throughorifice into a quenching medium and thereafter stretching the resultingfilament, the improvement comprising dispersing in the extrudate priorto extrusion at least 0.1 percent by weight, based on the Weight of thepolyamide polymer, of an amino acid salt having the formula:

where R is an alkyl radical containing at least 6 carbon atoms, R is analkyl radical containing at least 1 carbon atom, M is selected from thegroup consisting of alkali metals and alkaline earth metals and n is awhole number corresponding to the valence of the metal.

2. The process of claim 1 wherein 0.5 percent to 8 percent by weight ofthe amino acid salt is incorporated into the fiber, based on the weightof the polyamide.

3. The process of claim 2 wherein the polyamide contains about 2 percentto about 8 percent by weight of said antistatic tetrol compound.

4. The process of claim 2 wherein the amino acid salt has the formula:

where R is an alkyl radical containing 8 to 16 carbon atoms, R is analkyl radical containing 1 to 4 carbon atoms and M is an alkali metal.

5. The process of claim 2 wherein the weight ratio of the amino acidsalt to the antistatic tetrol compound is between 0.02 and 0.2.

6. An improved antistatic fiber consisting essentially of polyamide andabout 1 percent to 12 percent by weight of an antistatic tetrol compoundrepresented by the formula:

wherein a, b, c, a, e, f, g, and h are each a whole number and the totalof a, b, c, and d is between 8 and 850 and the total of e, f, g, and his between 8 and 1,000, and wherein the molecular weight of saidantistatic tetrol compound is between about 4,000 and about 50,000, saidethylene oxide moieties making up about 20 percent to about percent ofthe molecular weight of said compound; and at least 0.1 percent byweight, based on the weight of the polyamide of an amino acid salthaving the formula:

Where R is an alkyl radical containing at least 6 carbon atoms, R is analkyl radical containing at least 1 carbon atom, and M is selected fromthe group consisting of alkali metals and alkaline earth metals, and nis a whole number corresponding to the valence of the metal.

7. The fiber of claim 6 wherein 0.5 percent to 8 percent by weight ofthe amino acid salt is incorporated into the fiber, based on the weightof the polyamide.

8. The fiber of claim 7 wherein the polyamide contains about 2 percentto about 8 percent by weight of said antistatic tetrol compound.

9. The fiber of claim 7 wherein the amino acid salt has the formula:

where R is an alkyl radical containing 8 to 16 carbon atoms, R is analkyl radical containing 1 to 4 carbon atoms and M is an alkali metal.

10. The fiber of claim 7 wherein the weight ratio of the amino acid saltto the antistatic tetrol compound is between 0.02 and 0.2.

References Cited UNITED STATES PATENTS 2,729,657 1/1956 Krems 2604043,074,980 1/ 1963 Lorentzen 260-404 3,297,653 1/1967 Tomiyama 26078 S3,657,386 4/ 1972 Weedon 260857 PG PAUL LIEBERMAN, Primary Examiner US.Cl. X.R.

